[mirror_ubuntu-zesty-kernel.git] / drivers / md / dm-stripe.c

/*
 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
 *
 * This file is released under the GPL.
 */

#include <linux/device-mapper.h>

#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/log2.h>

#define DM_MSG_PREFIX "striped"
#define DM_IO_ERROR_THRESHOLD 15

struct stripe {
	struct dm_dev *dev;
	sector_t physical_start;

	atomic_t error_count;
};

struct stripe_c {
	uint32_t stripes;
	int stripes_shift;

	/* The size of this target / num. stripes */
	sector_t stripe_width;

	/* stripe chunk size */
	uint32_t chunk_shift;
	sector_t chunk_mask;

	/* Needed for handling events */
	struct dm_target *ti;

	/* Work struct used for triggering events*/
	struct work_struct trigger_event;

	struct stripe stripe[0];
};

/*
 * An event is triggered whenever a drive
 * drops out of a stripe volume.
 */
static void trigger_event(struct work_struct *work)
{
	struct stripe_c *sc = container_of(work, struct stripe_c,
					   trigger_event);
	dm_table_event(sc->ti->table);
}

static inline struct stripe_c *alloc_context(unsigned int stripes)
{
	size_t len;

	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
			     stripes))
		return NULL;

	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);

	return kmalloc(len, GFP_KERNEL);
}

/*
 * Parse a single <dev> <sector> pair
 */
static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
		      unsigned int stripe, char **argv)
{
	unsigned long long start;
	char dummy;

	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
		return -EINVAL;

	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
			  &sc->stripe[stripe].dev))
		return -ENXIO;

	sc->stripe[stripe].physical_start = start;

	return 0;
}

/*
 * Construct a striped mapping.
 * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
 */
static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	struct stripe_c *sc;
	sector_t width;
	uint32_t stripes;
	uint32_t chunk_size;
	int r;
	unsigned int i;

	if (argc < 2) {
		ti->error = "Not enough arguments";
		return -EINVAL;
	}

	if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
		ti->error = "Invalid stripe count";
		return -EINVAL;
	}

	if (kstrtouint(argv[1], 10, &chunk_size)) {
		ti->error = "Invalid chunk_size";
		return -EINVAL;
	}

	/*
	 * chunk_size is a power of two
	 */
	if (!is_power_of_2(chunk_size) ||
	    (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
		ti->error = "Invalid chunk size";
		return -EINVAL;
	}

	if (ti->len & (chunk_size - 1)) {
		ti->error = "Target length not divisible by "
		    "chunk size";
		return -EINVAL;
	}

	if (sector_div(width, stripes)) {
		ti->error = "Target length not divisible by "
		    "number of stripes";
		return -EINVAL;
	}

	/*
	 * Do we have enough arguments for that many stripes ?
	 */
	if (argc != (2 + 2 * stripes)) {
		ti->error = "Not enough destinations "
			"specified";
		return -EINVAL;
	}

	sc = alloc_context(stripes);
	if (!sc) {
		ti->error = "Memory allocation for striped context "
		    "failed";
		return -ENOMEM;
	}

	INIT_WORK(&sc->trigger_event, trigger_event);

	/* Set pointer to dm target; used in trigger_event */
	sc->ti = ti;
	sc->stripes = stripes;
	sc->stripe_width = width;

	if (stripes & (stripes - 1))
		sc->stripes_shift = -1;
	else
		sc->stripes_shift = __ffs(stripes);

	r = dm_set_target_max_io_len(ti, chunk_size);
	if (r)
		return r;

	ti->num_flush_requests = stripes;
	ti->num_discard_requests = stripes;

	sc->chunk_shift = ffs(chunk_size) - 1;
	sc->chunk_mask = ((sector_t) chunk_size) - 1;

	/*
	 * Get the stripe destinations.
	 */
	for (i = 0; i < stripes; i++) {
		argv += 2;

		r = get_stripe(ti, sc, i, argv);
		if (r < 0) {
			ti->error = "Couldn't parse stripe destination";
			while (i--)
				dm_put_device(ti, sc->stripe[i].dev);
			kfree(sc);
			return r;
		}
		atomic_set(&(sc->stripe[i].error_count), 0);
	}

	ti->private = sc;

	return 0;
}

static void stripe_dtr(struct dm_target *ti)
{
	unsigned int i;
	struct stripe_c *sc = (struct stripe_c *) ti->private;

	for (i = 0; i < sc->stripes; i++)
		dm_put_device(ti, sc->stripe[i].dev);

	flush_work_sync(&sc->trigger_event);
	kfree(sc);
}

static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
			      uint32_t *stripe, sector_t *result)
{
	sector_t offset = dm_target_offset(sc->ti, sector);
	sector_t chunk = offset >> sc->chunk_shift;

	if (sc->stripes_shift < 0)
		*stripe = sector_div(chunk, sc->stripes);
	else {
		*stripe = chunk & (sc->stripes - 1);
		chunk >>= sc->stripes_shift;
	}

	*result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask);
}

static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
				    uint32_t target_stripe, sector_t *result)
{
	uint32_t stripe;

	stripe_map_sector(sc, sector, &stripe, result);
	if (stripe == target_stripe)
		return;
	*result &= ~sc->chunk_mask;			/* round down */
	if (target_stripe < stripe)
		*result += sc->chunk_mask + 1;		/* next chunk */
}

static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
			      uint32_t target_stripe)
{
	sector_t begin, end;

	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
				target_stripe, &end);
	if (begin < end) {
		bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
		bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
		bio->bi_size = to_bytes(end - begin);
		return DM_MAPIO_REMAPPED;
	} else {
		/* The range doesn't map to the target stripe */
		bio_endio(bio, 0);
		return DM_MAPIO_SUBMITTED;
	}
}

static int stripe_map(struct dm_target *ti, struct bio *bio,
		      union map_info *map_context)
{
	struct stripe_c *sc = ti->private;
	uint32_t stripe;
	unsigned target_request_nr;

	if (bio->bi_rw & REQ_FLUSH) {
		target_request_nr = map_context->target_request_nr;
		BUG_ON(target_request_nr >= sc->stripes);
		bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
		return DM_MAPIO_REMAPPED;
	}
	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
		target_request_nr = map_context->target_request_nr;
		BUG_ON(target_request_nr >= sc->stripes);
		return stripe_map_discard(sc, bio, target_request_nr);
	}

	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);

	bio->bi_sector += sc->stripe[stripe].physical_start;
	bio->bi_bdev = sc->stripe[stripe].dev->bdev;

	return DM_MAPIO_REMAPPED;
}

/*
 * Stripe status:
 *
 * INFO
 * #stripes [stripe_name <stripe_name>] [group word count]
 * [error count 'A|D' <error count 'A|D'>]
 *
 * TABLE
 * #stripes [stripe chunk size]
 * [stripe_name physical_start <stripe_name physical_start>]
 *
 */

static int stripe_status(struct dm_target *ti,
			 status_type_t type, char *result, unsigned int maxlen)
{
	struct stripe_c *sc = (struct stripe_c *) ti->private;
	char buffer[sc->stripes + 1];
	unsigned int sz = 0;
	unsigned int i;

	switch (type) {
	case STATUSTYPE_INFO:
		DMEMIT("%d ", sc->stripes);
		for (i = 0; i < sc->stripes; i++)  {
			DMEMIT("%s ", sc->stripe[i].dev->name);
			buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
				'D' : 'A';
		}
		buffer[i] = '\0';
		DMEMIT("1 %s", buffer);
		break;

	case STATUSTYPE_TABLE:
		DMEMIT("%d %llu", sc->stripes,
			(unsigned long long)sc->chunk_mask + 1);
		for (i = 0; i < sc->stripes; i++)
			DMEMIT(" %s %llu", sc->stripe[i].dev->name,
			    (unsigned long long)sc->stripe[i].physical_start);
		break;
	}
	return 0;
}

static int stripe_end_io(struct dm_target *ti, struct bio *bio,
			 int error, union map_info *map_context)
{
	unsigned i;
	char major_minor[16];
	struct stripe_c *sc = ti->private;

	if (!error)
		return 0; /* I/O complete */

	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
		return error;

	if (error == -EOPNOTSUPP)
		return error;

	memset(major_minor, 0, sizeof(major_minor));
	sprintf(major_minor, "%d:%d",
		MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
		MINOR(disk_devt(bio->bi_bdev->bd_disk)));

	/*
	 * Test to see which stripe drive triggered the event
	 * and increment error count for all stripes on that device.
	 * If the error count for a given device exceeds the threshold
	 * value we will no longer trigger any further events.
	 */
	for (i = 0; i < sc->stripes; i++)
		if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
			atomic_inc(&(sc->stripe[i].error_count));
			if (atomic_read(&(sc->stripe[i].error_count)) <
			    DM_IO_ERROR_THRESHOLD)
				schedule_work(&sc->trigger_event);
		}

	return error;
}

static int stripe_iterate_devices(struct dm_target *ti,
				  iterate_devices_callout_fn fn, void *data)
{
	struct stripe_c *sc = ti->private;
	int ret = 0;
	unsigned i = 0;

	do {
		ret = fn(ti, sc->stripe[i].dev,
			 sc->stripe[i].physical_start,
			 sc->stripe_width, data);
	} while (!ret && ++i < sc->stripes);

	return ret;
}

static void stripe_io_hints(struct dm_target *ti,
			    struct queue_limits *limits)
{
	struct stripe_c *sc = ti->private;
	unsigned chunk_size = (sc->chunk_mask + 1) << 9;

	blk_limits_io_min(limits, chunk_size);
	blk_limits_io_opt(limits, chunk_size * sc->stripes);
}

static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
			struct bio_vec *biovec, int max_size)
{
	struct stripe_c *sc = ti->private;
	sector_t bvm_sector = bvm->bi_sector;
	uint32_t stripe;
	struct request_queue *q;

	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);

	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	if (!q->merge_bvec_fn)
		return max_size;

	bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
	bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;

	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
}

static struct target_type stripe_target = {
	.name   = "striped",
	.version = {1, 4, 0},
	.module = THIS_MODULE,
	.ctr    = stripe_ctr,
	.dtr    = stripe_dtr,
	.map    = stripe_map,
	.end_io = stripe_end_io,
	.status = stripe_status,
	.iterate_devices = stripe_iterate_devices,
	.io_hints = stripe_io_hints,
	.merge  = stripe_merge,
};

int __init dm_stripe_init(void)
{
	int r;

	r = dm_register_target(&stripe_target);
	if (r < 0) {
		DMWARN("target registration failed");
		return r;
	}

	return r;
}

void dm_stripe_exit(void)
{
	dm_unregister_target(&stripe_target);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Copyright (C) 2001-2003 Sistina Software (UK) Limited.
	3	*
	4	* This file is released under the GPL.
	5	*/
	6
586e80e6	7	#include <linux/device-mapper.h>
1da177e4 LT	8
	9	#include <linux/module.h>
	10	#include <linux/init.h>
	11	#include <linux/blkdev.h>
	12	#include <linux/bio.h>
	13	#include <linux/slab.h>
6f3c3f0a	14	#include <linux/log2.h>
1da177e4	15
72d94861	16	#define DM_MSG_PREFIX "striped"
a25eb944	17	#define DM_IO_ERROR_THRESHOLD 15
72d94861	18
1da177e4 LT	19	struct stripe {
	20	struct dm_dev *dev;
	21	sector_t physical_start;
a25eb944 BW	22
a25eb944 BW	23	atomic_t error_count;
1da177e4 LT	24	};
	25
	26	struct stripe_c {
	27	uint32_t stripes;
c96053b7	28	int stripes_shift;
1da177e4 LT	29
	30	/* The size of this target / num. stripes */
	31	sector_t stripe_width;
	32
	33	/* stripe chunk size */
	34	uint32_t chunk_shift;
	35	sector_t chunk_mask;
	36
a25eb944 BW	37	/* Needed for handling events */
	38	struct dm_target *ti;
	39
	40	/* Work struct used for triggering events*/
f521f074	41	struct work_struct trigger_event;
a25eb944	42
1da177e4 LT	43	struct stripe stripe[0];
	44	};
	45
a25eb944 BW	46	/*
	47	* An event is triggered whenever a drive
	48	* drops out of a stripe volume.
	49	*/
	50	static void trigger_event(struct work_struct *work)
	51	{
f521f074 TH	52	struct stripe_c *sc = container_of(work, struct stripe_c,
f521f074 TH	53	trigger_event);
a25eb944	54	dm_table_event(sc->ti->table);
a25eb944 BW	55	}
a25eb944 BW	56
1da177e4 LT	57	static inline struct stripe_c *alloc_context(unsigned int stripes)
	58	{
	59	size_t len;
	60
d63a5ce3 MP	61	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
d63a5ce3 MP	62	stripes))
1da177e4 LT	63	return NULL;
	64
	65	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
	66
	67	return kmalloc(len, GFP_KERNEL);
	68	}
	69
	70	/*
	71	* Parse a single <dev> <sector> pair
	72	*/
	73	static int get_stripe(struct dm_target ti, struct stripe_c sc,
	74	unsigned int stripe, char **argv)
	75	{
4ee218cd	76	unsigned long long start;
31998ef1	77	char dummy;
1da177e4	78
31998ef1	79	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
1da177e4 LT	80	return -EINVAL;
1da177e4 LT	81
8215d6ec	82	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
1da177e4 LT	83	&sc->stripe[stripe].dev))
	84	return -ENXIO;
	85
	86	sc->stripe[stripe].physical_start = start;
a25eb944	87
1da177e4 LT	88	return 0;
	89	}
	90
	91	/*
	92	* Construct a striped mapping.
	93	* <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
	94	*/
	95	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	96	{
	97	struct stripe_c *sc;
	98	sector_t width;
	99	uint32_t stripes;
	100	uint32_t chunk_size;
1da177e4 LT	101	int r;
	102	unsigned int i;
	103
	104	if (argc < 2) {
72d94861	105	ti->error = "Not enough arguments";
1da177e4 LT	106	return -EINVAL;
	107	}
	108
1a66a08a	109	if (kstrtouint(argv[0], 10, &stripes) \|\| !stripes) {
72d94861	110	ti->error = "Invalid stripe count";
1da177e4 LT	111	return -EINVAL;
	112	}
	113
1a66a08a	114	if (kstrtouint(argv[1], 10, &chunk_size)) {
72d94861	115	ti->error = "Invalid chunk_size";
1da177e4 LT	116	return -EINVAL;
	117	}
	118
	119	/*
	120	* chunk_size is a power of two
	121	*/
6f3c3f0a	122	if (!is_power_of_2(chunk_size) \|\|
1da177e4	123	(chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
72d94861	124	ti->error = "Invalid chunk size";
1da177e4 LT	125	return -EINVAL;
	126	}
	127
a22c96c7	128	if (ti->len & (chunk_size - 1)) {
72d94861	129	ti->error = "Target length not divisible by "
8ba32fde KC	130	"chunk size";
	131	return -EINVAL;
	132	}
	133
1da177e4	134	if (sector_div(width, stripes)) {
72d94861	135	ti->error = "Target length not divisible by "
1da177e4 LT	136	"number of stripes";
	137	return -EINVAL;
	138	}
	139
	140	/*
	141	* Do we have enough arguments for that many stripes ?
	142	*/
	143	if (argc != (2 + 2 * stripes)) {
72d94861	144	ti->error = "Not enough destinations "
1da177e4 LT	145	"specified";
	146	return -EINVAL;
	147	}
	148
	149	sc = alloc_context(stripes);
	150	if (!sc) {
72d94861	151	ti->error = "Memory allocation for striped context "
1da177e4 LT	152	"failed";
	153	return -ENOMEM;
	154	}
	155
f521f074	156	INIT_WORK(&sc->trigger_event, trigger_event);
a25eb944 BW	157
	158	/* Set pointer to dm target; used in trigger_event */
	159	sc->ti = ti;
1da177e4 LT	160	sc->stripes = stripes;
1da177e4 LT	161	sc->stripe_width = width;
c96053b7 MP	162
	163	if (stripes & (stripes - 1))
	164	sc->stripes_shift = -1;
1df05483 MP	165	else
1df05483 MP	166	sc->stripes_shift = __ffs(stripes);
c96053b7	167
542f9038 MS	168	r = dm_set_target_max_io_len(ti, chunk_size);
	169	if (r)
	170	return r;
	171
374bf7e7	172	ti->num_flush_requests = stripes;
7b76ec11	173	ti->num_discard_requests = stripes;
1da177e4	174
c96053b7	175	sc->chunk_shift = ffs(chunk_size) - 1;
1da177e4	176	sc->chunk_mask = ((sector_t) chunk_size) - 1;
1da177e4 LT	177
	178	/*
	179	* Get the stripe destinations.
	180	*/
	181	for (i = 0; i < stripes; i++) {
	182	argv += 2;
	183
	184	r = get_stripe(ti, sc, i, argv);
	185	if (r < 0) {
72d94861	186	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	187	while (i--)
	188	dm_put_device(ti, sc->stripe[i].dev);
	189	kfree(sc);
	190	return r;
	191	}
a25eb944	192	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	193	}
	194
	195	ti->private = sc;
a25eb944	196
1da177e4 LT	197	return 0;
	198	}
	199
	200	static void stripe_dtr(struct dm_target *ti)
	201	{
	202	unsigned int i;
	203	struct stripe_c sc = (struct stripe_c ) ti->private;
	204
	205	for (i = 0; i < sc->stripes; i++)
	206	dm_put_device(ti, sc->stripe[i].dev);
	207
f521f074	208	flush_work_sync(&sc->trigger_event);
1da177e4 LT	209	kfree(sc);
	210	}
	211
65988525 MP	212	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	213	uint32_t stripe, sector_t result)
	214	{
	215	sector_t offset = dm_target_offset(sc->ti, sector);
	216	sector_t chunk = offset >> sc->chunk_shift;
	217
c96053b7 MP	218	if (sc->stripes_shift < 0)
	219	*stripe = sector_div(chunk, sc->stripes);
	220	else {
1df05483	221	*stripe = chunk & (sc->stripes - 1);
c96053b7 MP	222	chunk >>= sc->stripes_shift;
	223	}
	224
65988525 MP	225	*result = (chunk << sc->chunk_shift) \| (offset & sc->chunk_mask);
	226	}
	227
7b76ec11 MP	228	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	229	uint32_t target_stripe, sector_t *result)
	230	{
	231	uint32_t stripe;
	232
	233	stripe_map_sector(sc, sector, &stripe, result);
	234	if (stripe == target_stripe)
	235	return;
	236	result &= ~sc->chunk_mask; / round down */
	237	if (target_stripe < stripe)
	238	result += sc->chunk_mask + 1; / next chunk */
	239	}
	240
	241	static int stripe_map_discard(struct stripe_c sc, struct bio bio,
	242	uint32_t target_stripe)
	243	{
	244	sector_t begin, end;
	245
	246	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
	247	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
	248	target_stripe, &end);
	249	if (begin < end) {
	250	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
	251	bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
	252	bio->bi_size = to_bytes(end - begin);
	253	return DM_MAPIO_REMAPPED;
	254	} else {
	255	/* The range doesn't map to the target stripe */
	256	bio_endio(bio, 0);
	257	return DM_MAPIO_SUBMITTED;
	258	}
	259	}
	260
1da177e4 LT	261	static int stripe_map(struct dm_target ti, struct bio bio,
	262	union map_info *map_context)
	263	{
65988525	264	struct stripe_c *sc = ti->private;
374bf7e7	265	uint32_t stripe;
57cba5d3	266	unsigned target_request_nr;
1da177e4	267
d87f4c14	268	if (bio->bi_rw & REQ_FLUSH) {
57cba5d3 MS	269	target_request_nr = map_context->target_request_nr;
	270	BUG_ON(target_request_nr >= sc->stripes);
	271	bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
374bf7e7 MP	272	return DM_MAPIO_REMAPPED;
374bf7e7 MP	273	}
7b76ec11 MP	274	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
	275	target_request_nr = map_context->target_request_nr;
	276	BUG_ON(target_request_nr >= sc->stripes);
	277	return stripe_map_discard(sc, bio, target_request_nr);
	278	}
374bf7e7	279
65988525	280	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
1da177e4	281
65988525	282	bio->bi_sector += sc->stripe[stripe].physical_start;
1da177e4	283	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	284
d2a7ad29	285	return DM_MAPIO_REMAPPED;
1da177e4 LT	286	}
1da177e4 LT	287
4f7f5c67 BW	288	/*
	289	* Stripe status:
	290	*
	291	* INFO
	292	* #stripes [stripe_name <stripe_name>] [group word count]
	293	* [error count 'A\|D' <error count 'A\|D'>]
	294	*
	295	* TABLE
	296	* #stripes [stripe chunk size]
	297	* [stripe_name physical_start <stripe_name physical_start>]
	298	*
	299	*/
	300
1da177e4 LT	301	static int stripe_status(struct dm_target *ti,
	302	status_type_t type, char *result, unsigned int maxlen)
	303	{
	304	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	305	char buffer[sc->stripes + 1];
1da177e4 LT	306	unsigned int sz = 0;
	307	unsigned int i;
	308
	309	switch (type) {
	310	case STATUSTYPE_INFO:
4f7f5c67 BW	311	DMEMIT("%d ", sc->stripes);
	312	for (i = 0; i < sc->stripes; i++) {
	313	DMEMIT("%s ", sc->stripe[i].dev->name);
	314	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	315	'D' : 'A';
	316	}
	317	buffer[i] = '\0';
	318	DMEMIT("1 %s", buffer);
1da177e4 LT	319	break;
	320
	321	case STATUSTYPE_TABLE:
4ee218cd AM	322	DMEMIT("%d %llu", sc->stripes,
4ee218cd AM	323	(unsigned long long)sc->chunk_mask + 1);
1da177e4	324	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	325	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	326	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	327	break;
	328	}
	329	return 0;
	330	}
	331
a25eb944 BW	332	static int stripe_end_io(struct dm_target ti, struct bio bio,
	333	int error, union map_info *map_context)
	334	{
	335	unsigned i;
	336	char major_minor[16];
	337	struct stripe_c *sc = ti->private;
	338
	339	if (!error)
	340	return 0; /* I/O complete */
	341
7b6d91da	342	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	343	return error;
	344
	345	if (error == -EOPNOTSUPP)
	346	return error;
	347
	348	memset(major_minor, 0, sizeof(major_minor));
	349	sprintf(major_minor, "%d:%d",
f331c029 TH	350	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	351	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	352
	353	/*
	354	* Test to see which stripe drive triggered the event
	355	* and increment error count for all stripes on that device.
	356	* If the error count for a given device exceeds the threshold
	357	* value we will no longer trigger any further events.
	358	*/
	359	for (i = 0; i < sc->stripes; i++)
	360	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	361	atomic_inc(&(sc->stripe[i].error_count));
	362	if (atomic_read(&(sc->stripe[i].error_count)) <
	363	DM_IO_ERROR_THRESHOLD)
f521f074	364	schedule_work(&sc->trigger_event);
a25eb944 BW	365	}
	366
	367	return error;
	368	}
	369
af4874e0 MS	370	static int stripe_iterate_devices(struct dm_target *ti,
	371	iterate_devices_callout_fn fn, void *data)
	372	{
	373	struct stripe_c *sc = ti->private;
	374	int ret = 0;
	375	unsigned i = 0;
	376
5dea271b	377	do {
af4874e0	378	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	379	sc->stripe[i].physical_start,
	380	sc->stripe_width, data);
	381	} while (!ret && ++i < sc->stripes);
af4874e0 MS	382
	383	return ret;
	384	}
	385
40bea431 MS	386	static void stripe_io_hints(struct dm_target *ti,
	387	struct queue_limits *limits)
	388	{
	389	struct stripe_c *sc = ti->private;
	390	unsigned chunk_size = (sc->chunk_mask + 1) << 9;
	391
	392	blk_limits_io_min(limits, chunk_size);
3c5820c7	393	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	394	}
40bea431 MS	395
29915202 MM	396	static int stripe_merge(struct dm_target ti, struct bvec_merge_data bvm,
	397	struct bio_vec *biovec, int max_size)
	398	{
	399	struct stripe_c *sc = ti->private;
	400	sector_t bvm_sector = bvm->bi_sector;
	401	uint32_t stripe;
	402	struct request_queue *q;
	403
	404	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
	405
	406	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	407	if (!q->merge_bvec_fn)
	408	return max_size;
	409
	410	bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
	411	bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
	412
	413	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	414	}
	415
1da177e4 LT	416	static struct target_type stripe_target = {
1da177e4 LT	417	.name = "striped",
29915202	418	.version = {1, 4, 0},
1da177e4 LT	419	.module = THIS_MODULE,
	420	.ctr = stripe_ctr,
	421	.dtr = stripe_dtr,
	422	.map = stripe_map,
a25eb944	423	.end_io = stripe_end_io,
1da177e4	424	.status = stripe_status,
af4874e0	425	.iterate_devices = stripe_iterate_devices,
40bea431	426	.io_hints = stripe_io_hints,
29915202	427	.merge = stripe_merge,
1da177e4 LT	428	};
	429
	430	int __init dm_stripe_init(void)
	431	{
	432	int r;
	433
	434	r = dm_register_target(&stripe_target);
6edebdee	435	if (r < 0) {
72d94861	436	DMWARN("target registration failed");
6edebdee HM	437	return r;
6edebdee HM	438	}
1da177e4 LT	439
	440	return r;
	441	}
	442
	443	void dm_stripe_exit(void)
	444	{
10d3bd09	445	dm_unregister_target(&stripe_target);
1da177e4	446	}